Studies of the fluorescent pigment lipofuscin, which accumulates in vitamin E deficient rat uterus, showed that the formation of the pigment in this tissue is unaffected by the animal's vitamin A status. It was concluded that vitamin A cannot be a significant component of lipofuscin. Quantification of the pigment by determining the fluorescence of lipid extracts from affected uteri was found not to give a reliable estimate of the extent of lipofuscin deposition. A rapid micro method, utilizing high pressure liquid chromatography, was developed for the simultaneous determination of vitamins A and E in blood plasma and red cells.